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01-线上问题处理-树形结构拼接

news 2025/9/8 21:39:54

1 递归方式实现

1.1 代码

步骤一：一次性获取到所有的数据tisManualCatalogPOS
步骤二：获取到一级节点(parentId为null)
步骤三：递归向下拼接
树的深度很深，导致堆栈越多，可能

生产8K的数据能很明显的看到接口响应慢，<没打印日志>

  private List<ManualTreeVO> buildTree(List<TisManualCatalogPO> tisManualCatalogPOS) {List<ManualTreeVO> treeVOList = Lists.newArrayList();if (CollectionUtils.isEmpty(tisManualCatalogPOS)) {return treeVOList;}List<ManualTreeVO> dataList = tisManualCatalogPOS.stream().map(x -> {ManualTreeVO bean = new ManualTreeVO();bean.setId(x.getId());bean.setName(x.getName());bean.setSort(x.getSort());bean.setType(x.getType());bean.setCode(x.getCode());bean.setParentId(x.getParentId());String filePath = x.getFilePath();// 不包含则拼前缀if (StringUtils.isNotEmpty(filePath) && !filePath.contains(filePathPrefix)) {filePath = filePathPrefix + filePath;}bean.setFilePath(filePath);return bean;}).collect(Collectors.toList());// 拿到所有的一级节点List<ManualTreeVO> firstCatalogList = dataList.stream().filter(x -> Objects.isNull(x.getParentId())).sorted(Comparator.comparing(ManualTreeVO::getSort)).collect(Collectors.toList());for (ManualTreeVO data : firstCatalogList) {// 构建树doBuildTree(dataList, data);treeVOList.add(data);}return treeVOList;}private void doBuildTree(List<ManualTreeVO> hoursCatalogList, ManualTreeVO treeVO) {// 下一级List<ManualTreeVO> childrenList = getChildrenList(hoursCatalogList, treeVO);treeVO.setChildrenList(childrenList);for (ManualTreeVO children : childrenList) {// 有下级if (!CollectionUtils.isEmpty(getChildrenList(hoursCatalogList, children))) {doBuildTree(hoursCatalogList, children);}}}private List<ManualTreeVO> getChildrenList(List<ManualTreeVO> hoursCatalogList, ManualTreeVO treeVO) {// 下一级List<ManualTreeVO> nextList = hoursCatalogList.stream().filter(x -> Objects.equals(treeVO.getCode(), x.getParentId())).sorted(Comparator.comparing(ManualTreeVO::getSort)).collect(Collectors.toList());return nextList;}

1.2 性能

2 非递归方式实现(推荐)

2.1 代码

使用Map，哈希的方式用空间换时间，一次遍历即可拼接成树

    public List<ManualTreeVO> buildTreeNew(String uuid, List<TisManualCatalogPO> tisManualCatalogPOS) {log.info("手册目录-拼接目录 uuid {} {}", uuid, CollectionUtils.isNotEmpty(tisManualCatalogPOS) ? tisManualCatalogPOS.size() : 0);List<ManualTreeVO> roots = Lists.newArrayList();Map<String, ManualTreeVO> nodeMap = new HashMap<>();List<ManualTreeVO> dataList = tisManualCatalogPOS.stream().map(x -> {ManualTreeVO bean = new ManualTreeVO();bean.setId(x.getId());bean.setName(x.getName());bean.setSort(x.getSort());bean.setType(x.getType());bean.setCode(x.getCode());bean.setParentId(x.getParentId());String filePath = x.getFilePath();// 不包含则拼前缀if (StringUtils.isNotEmpty(filePath) && !filePath.contains(filePathPrefix)) {filePath = filePathPrefix + filePath;}bean.setFilePath(filePath);return bean;}).collect(Collectors.toList());// 将所有节点存入映射表for (ManualTreeVO node : dataList) {nodeMap.put(node.getCode(), node);}// 构建树结构for (ManualTreeVO node : dataList) {String parentId = node.getParentId();if (parentId == null || parentId.isEmpty()) {roots.add(node);} else {ManualTreeVO parent = nodeMap.get(parentId);if (parent != null) {parent.addChild(node);} else {// 如果父节点不存在，将其作为根节点roots.add(node);}}}log.info("手册目录-拼接目录 uuid end {}", uuid);return roots;}